What number was retired across all of MLB in honor of Jackie Robinson?

On this day in history, Jan. 31, 1919, Jackie Robinson is born in Georgia — baseball pioneer, WWII veteran

Jackie Robinson Day 2023: The eternal impact of No. 42

Last player to wear No. 42 for each MLB team

Honoring Robinson's Achievement and Carrying On His Legacy - The New York Times

San Diego Padres: Celebrating Jackie Robinson Day

Robinson, Jackie Baseball Hall of Fame

Uncle Mike's Musings: A Yankees Blog and More: April 15, 1947: We Are All Number 42

Hot take: Roberto Clemente Day should be just like Jackie Robinson Day💯⚾️ : r/mlb

Red Sox acknowledge uncomfortable reality on Jackie Robinson Day: No Black players on the roster - The Boston Globe